Educational appliance for aircraft navigation



Dec. 31, 1940. E. KRAMAR 2,226,726

EDUCATIONAL APPLIANCE FOR AIRCRAFT NAVIGATION Filed Oct. 15, 1957Patented Dec. 31, 1940 EDUCATIONAL APPLIANCE FOB, AIRCRAFT NAVIGATIONErnst Kramar, Berlin-Tempelhof, Germany, as-

signor to C. Lorenz Akticngesellschaft, Berlin-- Tempelhoi', Germany, acompany Application October 15, 1937, Serial No. 169,244 In GermanyOctober 15, 1936 7 Claims.

The present invention relates to an apparatus for familiarizing a novicewith visual and audible signals encountered in radio systems for guidingaircraft. 4

The well-known radio landing beacon operates by radiating two differentbut complementary signals which, when heard at equal amplitude, willmerge into a continuous dash. This continuous dash can be heard by thepilot only within a narrow areafthe landing or desired area. To theright of this area one of the signals, and to the left of the area theother signal radiated by the beacon is heard.

In accordance with the present invention the landing area is visualized.An image representing the airplane is movable with respect to asimulated landing field, at the center of which a narrow sectorrepresents the area within which one must land, indicated in practice bythe continu ous dash signal.

tion has also an acoustic signaling arrangement. This acoustic signalingarrangement is automatically varied as the pupil varies the position ofthe airplane image.

Audible or visual or 'both kinds of signals are produced as in practice.flight by moving the image representing the air plane into any positionwith respect to the landing field, the acoustic device is automaticallyactuated to produce the kind of signal that would be produced inpractice in the earphones of a pilot by the landing beacon. The pupilwill thus learn the landing signals.

In addition to the acoustic signaling arrangement, 2. visual indicatoris also provided to teach I observation of deviations from the landingcourse.

The drawing represents an embodiment of the 4 present invention.

Fig. 1 is a partially diagrammatic front elevation of the arrangementchosen as an example. Fig. 2 shows a section through the appliance online 22 of Fig. 3. Fig. 3 represents a section on line 3-3 of Fig. 1.Fig. 4 is a fragmentary elevation that illustrates a detail arrangementmore fully referred to hereafter, Fig. 5 shows a section on line 5-5 ofFig. 4. Fig. 6 is a partially sectioned side view to Fig.- 4. Fig. 7diagrammatically illustrates a portion of the circuits an controllingmechanism.

Figs. 4, 5, 6 are drawn to a larger scale than Figs. 1, 2, 3.

The wall I of anopen box 32 has a sectorshaped aperture 2 which iscovered with a translucent pane I9, e. g., of ground glass. On panepivot A. A roller [2' is likewise carried by the As the pupil simulatesI9 a sector 3 is represented which has the same top or centre point ashas-aperture 2 and is provided with two characteristic markers 5, Ilocated in the neighbourhood of this centre point. Mounted in wall I areadjusting knobs I, I3 and apointer instrument II. On the back of wall Iand pane I9 a lever 6'is journaled on a pivot A. This lever is movablein the directions indicated by arrows c, Fig. 2, under the control of a,trac-- tion member 8 and of a spring 9. The traction member 8, forinstance a belt, is wound upon knob I or unwound therefrom depending onthe direction in which lever 6 is moved. Thus, by turning knob 'I leverB may be displaced over the aperture 2. When this is done a contact arm35 of the knob I slidesover contacts 33. Knob I3 has a contact arm 36intended to cooperate with two contacts 34.

In addition to lever 6 a roller I2 is mounted on wall structure I, I9.Lever 6 has a roller I2 fitted to its lower end. The rollers I2, I2, I2"and the knob I3 carry an endless belt II, for instance a wire. Belt IIis attached to a projector III which as indicated by the double arrow(1, Fig. 2, is displaceable along lever 6. The device I0 serves toproduce on pane I9 2. visual indication I4, for instance the image of anairplane.

The projector l0 comprises a shell 23, a glow lamp 20 disposed therein,and a cover disc 22 which as shown in Fig. 5 is rotatably fixed to theshell 23 and has an airplane shaped aperture 2 I. Shell 23 has adovetailed projection 30 which as shown in Fig. 5 fits in a longitudinalgroove 3I of the lever B. Disc 22 isunder the action of a frictionmember 24 whose length equals half the circumference of this disc. Thefriction member- 26, which may be of rubber, for instance, has aprojection 25 ateach end. Belt II is provided with two enlargements 26by which it is attached to the respective projection 25 in the mannerappearing from Fig. 6. Projecting-into the path of the projections 25are fingers 28 formed integral with a fiat bar 29 fixed to shell23. BeltII extendsthrough openings of the.'fingers 28. Fastened to the bar 29are guide members 21 adapted to aid the friction member 24 in its actionon the disc 22. When in Fig. 4 the upper part of the member II is pulledupwards, part 24, 25 by acting against the upper finger 28 takes with itthe device III which hence is displaced upward along lever 6 owing tothe dovetail guide .36, 3I.

When, however, the lower part of th member II is pulled downward, themotion of the member II .thusbeing reversed, the friction effective 5between the parts 24, 22 first causes the disc 22 to make ahalf-revolution whereby aperture 2| is brought to assume the oppositeposition-to that represented in Fig. 4. Part 24, 25 now comes againstthe lower flnger 28 so as to displace devic l0 downward along lever 6.

The contact arms 35, 36 and contacts 33, 34 serve for adjusting anarrangement of resistances not shown, over which a pair of headphone anda loudspeaker l6 can be connected with a device l8 that comprises acurrent generator and means for energizing the acoustic devices l5, l6periodically.

The arrangement is shown in Fig. 7. This arrangement is driven by amotor 31 which is fed from the mains supply. The shaft of the motor iscoupled with a generator 38 which produces the necessary alternatingfrequency and, moreover", this shaft carries two cam discs 39 and 40which open and close two contacts 4| and 42 in a periodic rhythm. Thecontacts 4| and. 42 control circuits in which the head set l5, or a loudspeaker (not shown), is inserted. The cams of the discs 39 and 40 havedifferent shapes so that one cam closes a contact while the other camopens a contact. The contacts 4t and 42 make and break in the samerhythm so that normally dots and dashes are transmitted. The resistancesare arranged as a potentiometer 33 on which the tap 35 is slid.Immediately after each cam of one of the said discs a cam of the otherdisc acts on the associated contact so that the tones produced by thesecontacts closing the circuits of the devices l5, [6 are combined into auniform permanent signal, the so called continuous dash line, if uponthe closing of one contact the same resistance is serially connected tothe devices I 5, 16 which was connected upon the closing of the othercontact. Such is the case, for instance, when knob I is in the positionshown in Figs. 1 and 2, that is, when contact arm 36 is in its uppermid-position. If however knob is turned out of this position then byclosing one of the contacts a greater resistance is connected in serieswith the devices l5, l6 than by closing the other contact. Owingto-thls, either the dashes will be louder than the dots'or vice versa,depending whether knob I is turned in one direction or the other.

Aperture 2 represents the space within which the aircraft must move inlanding. As long as the aircraft is within the space represented bysector 3 the pilot's head-phones, represented by the device l6, forinstance, reproduce the continuous dash line, that is, a permanent tone.This tone will assure the pilot that he is flying in the direction ofthe landing place, represented in my device-by the centre point of thesectors 2, 3. Whenever the,. aircraft happens to overfiy the right-handor leftboundary of the space here represented by sector 3, the toneheard by the pilot will change. When overflying one of the radialboundaries corresponding to the sector 3, the dashes preponderate, whilewhen overflying the other boundary the dotswlll preponderate. Theseindioationswill cause the pilot to alterthe course until he shall againhear the continuous dash line.

Instead of the dash-dot method any other suitablemethod may be employed,such as the so-called a-n method, for instance, with which the Horsesignals and Similarly, the said dashes and dots 'serve to complementeach other to make the continuous dash line. All

associated with the devices l5, l6.

aaeeyee these signals are in a well known manner emitted by theso-called keying of the reflectors or the like, alternately to renderthem efiective and'ineflective, for instance by opening and closingcontacts provided in the reflectors. Such arrangement is disclosed in myPatent No. 2,028,510. 7

Deviations from the proper course are in practice visualized by adirection indicator in the instrument board of the aircraft. The pilotwhen flying in the proper direction also receives two acoustic signalswhich advise him of the position of the aircraft. These two signals,known as warning signal and main signal may differ in pitch, e. g., thewarning signal may be a deep tone and the main signal a high tone. Thesetwo signals correspond to the characteristic signs or markers 5, 4 shownin Fig. 1.

The sign or image I 4 is movable in all directions within aperture 2 bydisplacing the projector I 0 along lever 6 and by displacing the leveritself.

The projector I 0 is displaced along lever 6 by turning the knob I3which with the aid of the belt II determines the position of device I0on lever 6. As soon as theimage I4, moved in the direction of the arrowb, arrives at the characteristic marker 6, contact arm 36 reaches one ofthe contacts 34, thus causing headphones l6 and loudspeaker Hi to beenergized. When image i4 arrives at the characteristic marker 4, arm 36reaches the other contact 34 and the devices I5, I 6 are again renderedefiective. In this way,

before landing, that is, before image l4 arrives '1 then acts toenergize the acoustic devices l6,

l6 over the contacts 33. Whenever lever 6 is turned in the direction ofthe arrow 0 shown on the right in Fig. 2, then corresponding to eachcontact 33 reached by arm 35, the dash signals, for instance, will beincreasing in loudness as compared to the dot signals the loudness ofwhich will be decreasing. This, as before described, is due to the factthat arm 35 by stepping from one of the contacts 33 to the next acts tovary the mutual ratio of series resistances Whenever lever 6 is turnedin the direction of the arrow 0 shown on the left in Fig. 2, then forthe same reason as before each step made by the arm 35 causes the dotsignals to increase in loudness over the dash signals, the loudness ofwhich is decreasing accordingly, as is the case also in practice.

'I'he position of the image [4 is indicated also optically, that is, bythe pointer instrument II that, corresponds to the direction indicatorof an aircraft.

It will be obvious from the foregoing description that the instrument asdescribed may be used in any suitable location, either on a practiceaircraft or an aircraft in operation under control of a pilot or evenapart from an aircraft as may be desired.

meansfor projecting an airplane image simulating the landing aircraft onsaid wall mounted on What is claimed is:

1. An appliance for instruction of aircraft pilots concerning aircraftguiding beam signals, comprising a wall having a sector simulating thearea over a landing field in which landing may be safely maderepresented thereon, a movable indicator simulating an aircraftpositioned in said sector, means for producing audible signalssimulating signals produced by radio beacons in aircraft receiverscontrolled by the position of said indicator within said sector andmeans for moving said indicator.

2. An appliance for the instruction of aircraft pilots concerningaircraft guiding beam signals, comprising a wall having a sectorsimulating a portion of the area over which a craft flies to a landingrepresented thereon, a movable indicator simulating an aircraftpositioned in said sector, a pointer instrument simulating an instrumentboard indicator for indicating the 'position of said movable indicatorin Said sector, and means for simultaneously moving said indicator andcontrolling said instrument.

3. An appliance according to claim 1 wherein said wall comprises atranslucent screen and said indicator comprises an airplane imageprojected on said screen.

4. An appliance for the instruction of aircraft pilots concerningaircraft guiding beam signals, comprising a wall having a sectorsimulating a po'rtionflof the area. over which a craft flies duringlanding represented thereon, a lever,

said lever and comprising a shell, 8. source of light disposed therein,and a rotatable cover disc fitted to said shell and provided with-anaperture in the shape of an airplane, means fordisplacing saidprojecting means along said lever "to move the portion of said imagewithin said, sector, means for rotating said cover controlled by thedirection of displacement of said projecting means, means for producingaudible signals simulating signals produced by radio beacons in aircraftreceivers, and meansfo'r moving said lever for controlling said signals.

5. An appliance according to claim 4 wherein said means for displacingsaid projecting means along said lever also controls means for furtherenergizing said means for producing audible signals at predetermineddisplacements of said projecting means simulating signals receivable ona craft for the particular position thereof.

6. An appliance according to claim 4 wherein said means for moving saidlever and controlling said signals comprises a resistance for varyingthe intensity of said signals.

'7. An appliance according to claim 4 having a second sector simulatingthe safe landing area for said craft, whose center coincides with thecenter of said first sector and whose angle is smaller than the angle ofsaid first sector.

ERNST KRAMAR.

